This project recieves Bluetooth signals from heart rate monitor then displayed it on serial ports and adjust the fan speed through PWM.

The buttons adjust the offset (fan speed) and the toggle switch swtiches between manual, auto, and neutral modes.

Manual mode set the fan speed by the offset value. Auto set the fan speed through Heart Rate plus offset. Neutral mode stops the fan.

The intension was to mimic somthing like Wahoo KICKR HEADWIND, this device also has the capability to send the recieved Heart Rate signals out for indoor cycling software such as Zwift, Rouvy, etc.

1x ESP32 dev board
1x 120mm 12V Fan with ARGB
1x Bluetooth Heart Rate Band or Smart Watch that could broadcast HR data through Bluetooth
1x 3 position toggle switch
2x Panel Mount buttons
1x 12V DC source
1x DC panel mount female plug
some wires

It's time to build it up! Follow the schematic shown above, then test it if it works. Then, for the casing I search up something related to this project and I found this. But since I am using a larger version of esp32, I had to redesign the bottom container and add four more holes for the buttons, switch, and the DC barrel. Here are the printed parts.

Then install the ESP32, buttons, switch, and the barrel plug to the container.

Finally, screw the screws and close the container.